Laminates including a glass fiber layer are known as interior materials or acoustic materials for cars, railway vehicles or vessels (see, for example, Patent Document 1). The laminate disclosed in Patent Document 1 has a layered structure shown in FIG. 2, namely, a structure in which glass fiber layers 2, 3 and surface material layers 4, 5 are disposed and adhered on both sides of a foam layer 1 of a polyurethane foam and shaped into a predetermined shape. For adhering and integrating the layers and fixing the shape, the following methods have been adopted; for example, a method in which a powder of a polyethylene resin or polypropylene resin is dispersed in the glass fiber layers 2, 3 and then the layers are held and pressed between molds while being heated at a temperature of about 170° C., so that the resin powder is melted, and then the melted resin is cooled to solidify; a method in which a liquid adhesive such as an isocyanate resin is sprayed to an adhered side of the foam 1; a method in which a resin layer which will serve as a binder is formed by transfer or the like; and a method in which a hot-melt sheet is heated and adhered with a calender or a thermal adhesion machine.
However, the aforementioned methods are not so desirable from the viewpoint of an environmental pollution problem and energy saving because it is necessary to conduct high-temperature or long-time heat treatment for the purpose of drying or welding of the resin. Hot-melt sheets or the like can be adhered only by pressuring at a high temperature of 170° C. or more and a high pressure of 0.5 kg/cm2 or more. Particularly, in adhering of a polyurethane-based hot-melt sheet, operations become complicated because the adhesion needs moisture and can not be achieved fully by only the moisture in the air, leading to require a step of supplying moisture. In addition, although the reaction starts on the absorption of moisture, the reaction will have not been completed when fixing by thermal adhesion is completed because it requires about 24 hours to complete the reaction. In the adhesion using such a binder resin, high-temperature and high-pressure adhesion will cause the resin to form a film at an interface between nonwoven fabrics and will reduce the thickness of a structure. Therefore, it has some problems such as deterioration in rigidity and sound absorbency.
A method is also known which uses, as an adhering layer, a spider web-like sheet obtained by spunbonding using a modified polyester fiber as a raw material instead of the binder resin or the urethane-based hot-melt sheet (see, for example, Patent Document 2). It, however, is problematic in that a high pressure of 0.5 kg/cm2 or more and a high temperature of 140° C. or more are required as adhering conditions in use of that sheet as an adhering layer and the failure to satisfy these conditions will lead to low adhesiveness to cause delamination of a laminate after molding.
Patent Document 1: JP 10-000716 A
Patent Document 2: JP 8-58003 A